Charge forming device



Jan. 16, 1934. F. E. ASELTINE CHARGE FORMING DEVIC E Filed Feb.

2 Sheets-Sheet l 3mm E12 1? 5 14759117175 Jan. 16, 1934. F. E. ASELTINECHARGE FORMING DEVICE Filed Feb. 1, 1930 2 Sheets-Sheet 2 Patented Jan.16, 1934 1 943 Hui fl fr- ,7; tliti ihii 1,943,909

CHARGE F-SRMRNG DEVICE Fred Aseltine, Dayton, Ohio, assignor to Del'co:

Products Corporation, Dayton, Ohio, at corporation of DelawareApplication February 1, 1930. Serial No. 425,221

21 Claims. (Cl. Zil34) This invention relates to charge forming devicesports of a multicylinder engine. The outlet for internal combustionengines, and more parbranches are each provided with an attachingticularly to devices of this character which comflange is for securingthe manifold to the engine prise a plurality of primary carburetors,which block in the usual manner, and a flange 18' to deliver a primarymixture of fuel and air to a which the carburetor unit is secured. 30

plurality of secondary mixing chambers located The carburetor unitcomprises a main housing adjacent the engine intake ports and in which20, having an attaching flange 22, adapted to be the primary mixture ismixed with additional secured to the flange 18 by screws 24. An air airunder certain operating conditions. inlet coupling 28 is secured inposition to register A device of this character is described in the withan opening in the upper wall of the hous- 5 copending application ofFred E. Aseltine, Wilinc 0, 111 a y Suitable y- A Casting in ford H.Teeter, and Carl Kindl, Serial No. which the passages supplying fuel tothe nozzles 288,683, filed June 2'7, 1928. are formed, is secured to thelower wall of hous- It is the principal object of the present inveninand a S e t eta uel bOWl 32 is held tion to provide improved means forenriching tight against an annular shoulder 34 on the 70 the mixtureduring the acceleration period. "With hous y any Suitable ea s- Fuel isconthis object in View, one feature of the invention ducted from a mainsource of supp y to the uel resides in the provision of means to supplyaddibowl throu a conduit (not shown) and the tional fuel to the mixturepassage during the ac- W Of fuel to e bOWl is controlled y a float 20celeration period following an opening movement Operating n the usualmanner maintain a Z5 of t th tt t gfleci iygngsg f hi h i isubstantially constant level of fuel therein. creased after the throttlehas made a prede- F1161 flows from the bowl 32 to a plurality 0 t minedopening mo ement, primary fuel nozzles 38, one of which is located Afurther feature of the invention consists in in a of he primary mixingChambers the 25 the provision of an open well, which is adapted o st ucton o w c is briefly described hereinto be filled with fuel on anyopening movement after. The fuel conduit between the fuel bowl of thethrottle and from which fuel is adapted to nd he nozzle comprises the vI f p a e be drawn by engine suction and delivered to the 42communicating at its pper end with the horsecondary air passage. izontalfuel canal 44, which connects with each 30 Another feature of theinvention is the proviof the nozzles 38 through an orifice 46. Fuel ission of an enriching device which is effective to admitted from the fuelbowl to the passage 42 at enrich the mixture to a greater extent andover all engine speeds, through a fixed metering oria longer period oftime following an opening of fice 48 and at high speeds additional fuelis adthe throttle when it is opened relatively slowly I initted throughan orifice 5O controlled by a valve 35 than on rapid opening movementsthereof. 52, operated in the manner set forth in the above Furtherobjects and advantages of the present mentioned application and formingno part of invention will be apparent from the following dethe presentinvention. scription, r :erence being had to the accompany- Fuel iscaused to flow from the fuel nozzles 38 ing drawings wherein a preferredembodiment of to the primary mixing chambers by the suction 40 one formof the present invention is clearly therein. A check valve 5a isprovided in an enshown. I larged chamber 56 at the junction of thechannels In the drawings: 42 and a4, and on reduction of mixing chamber1 is avertical, longitudinal section through suction following a.closing movement of the a charge forming device constructed inaccordthrottle seats on the bottom of the chamber, pre- 45 ance with thepresent invention and the intake venting downward flow of fuel.

port with which it is associated. Each primary fuel nozzle is providedwith a Figs. 2 and 3 are fragm ntary, detail sections main fuel outlet58 in the top of the nozzle and a on the lines and 3-3 of Fig. 1.secondary fuel outlet comprising two orifices 60 I Fig. 4 is anelevation partly in section. and 62 in the vertical wall of the nozzlenear the 0' Fig. 5 is a side elevation of the device showing bottom ofthe mixing chamber. At relatively the operating mechanism for thethrottle valves. speeds, the mixing chamber suction is suf- The devicedisclosed comprises a main air manificient to lift fuel from the mainoutlet as well as fold 10, having three outlet branches, the middle fromorifices 60 and 62. At idling, or low speed branch 12 being shownherein. Each of these operation under load, however, the suction is 55'branches communicates with one of the intake enough to lift fuel only tosome point between the top of the nozzle and the orifices and 62, fuelflowing from these orifices by the action of gravity under suchoperating conditions. Each nozzle is provided with a restricted fuelmetering orifice 63.

The primary mixing chambers comprise the enlarged anterior ends of theprimary mixture passages 64', which are parallel to each other and closetogether, as indicated in Fig. 2. When the carburetor is attached to themanifold, these passages register with conduits which convey the primarymixture to the secondary mixing chambers, as fully disclosed in theapplication above referred to, a tube 65 fixed in the middle outletbranch of the manifold constituting the conduit supplying the secondarymixing chamber associated with that particular branch. Restrictions 66separate the primary mixing chambers from the remainder of the mixturepassages to reduce the velocity of fiow past the fuel nozzles for thepurpose fully set forth in the above mentioned copending application.

A single throttle valve 68, which extends across all the primary mixturepassages, controls the flow therethrough and is provided with grooves70, which register with said mixture passages. This throttle is operatedin a manner hereinafter more fully described. The throttle also controlsa plurality of passages '71 which extend from the Y air chamber to theprimary mixture passages.

These passages admit additional air in advance of the fuel nozzles, andthe amount of air thus admitted is gradually reduced as the throttle isopened, the function of these passages being fully explained in theearlier application above referred to.

Air is admitted to the carburetor through the inlet coupling 28 and iscontrolled by the main air valve 74, normally held against a seat 76 bya spring Z8, received between the valve and a fiange 80, projecting froma sleeve 82, slidably mounted on a sleeve 84, fixed in the housing 20,and guiding the stem 86 to which the air valve is secured. When thecarburetor is choked to facilitate starting, the flange 80 is lifted bymeans not shown herein, but fully described in the above application,until the upper end of the sleeve 82 engages the air valve to hold itclosed. Sufficient air to carry the starting fuel from the nozzles tothe intake ports is admitted through an elongated slot 87, formed in aplate 88, secured to the housing 20, as shown in Fig. 1.

The valve 74 admits air to the air chamber 90, from which air flows tothe primary passage through an orifice 92 in the bottom of the airchamber and to the secondary mixing chambers through a passage 94, whichconnects with the inlet of the manifold 10, the how through this passagebeing controlled by a manually operable valve 96, and by a suctionoperated valve 100,

secured to shafts 98 and 102 respectively which are journalled in themain housing.

The operating connections for the throttle 68 and the valve 96 includean operating arm 101, which is secured in any suitable manner to aspindle 103 projecting from the end of the throttle valve 68 andextending outside the main housing 20. The operating arm 101 is providedat its free end with an orifice 105 in which any suitable form ofoperating connection which is adapted to extend to a point convenient tothe operator of the vehicle, may be secured. Secured to one end of theshaft 93 on which the valve 96 is mounted, is an operating arm 10'?secured to the shaft by a set screw 109. This operating arm is adaptedto be operated from the arm 101 as the primary throttle is openedthrough the medium of a lost motion connection comprising an operatinglink 111 pivotally secured by the screw 113 to the arm 101 and providedwith a slot 115 therein through which extends a screw 11'? screwed intothe arm 107. The screw is connected by a spring 11 to a lug 121 formedby bending over the upper end of the link 111 and is adapted to hold thescrew 11'? in the upper end of the slot 115 under certain conditions.Threaded in lugs 123, projecting from the link 111 is an ad- 'dstingscrew 125 which may be adjusted to limit the upward movement of the link111 relative to the arm 107, acting as a stop to prevent further movemenof the link when the screw 125 engages the screw 11'. and the valve 96is in closed position. In normal position of the parts when the engineis not running and the primary throttie is closed, the screw 11'? is inthe lower part of the slot 115 and engaging the screw 125 so that whenthe arm 101 is moved in a counter clockwise direction to open theprimary throttle some movement of the link 111 is permitted withoutcorresponding movement of the arm 107 until the link has moved to suchposition relative to the arm that the screw 117 engages the upper end ofthe slot 115. As has been pointed out before, the amount of thismovement may be adjusted by adjustment of the screw 125 and theadjustment is generally such that the primary throttle can be opened toa position corresponding to a vehicular speed of substantially 15 to 20miles per hour before any movement of the arm 10'? and the valve 96 cantake place.

On any increase of suction in the main air chamber, the air valve 74 isopened to admit additional air and its opening must be retarded toprevent fluttering thereof and to restrict the admission of airsufiiciently to enrich the mixture to some extent. This is accomplishedby a dashpot comprising a cylinder 104, which receives fuel from themain fuel reservoir and a piston 106, secured to the lower end of thevalve stem 86 by any suitable means, but the dashpot may be of any Iconventional form since its specific construction is not material to thepresent invention.

As above stated, it has been found necessary to provide a dashpot toretard the opening of the valve 109 whenever the valve 96 is opened, thepurpose of this dashpot and its construction being fully described inthe above application. The construction of this dashpot is in no waymaterial to the present invention and it is not illustrated herein forthe purpose of simplifying the disclosure.

In addition to retarding the opening of the main air valve for thepurpose of enriching the mixture during the acceleration period, a pumpis provided, which, according to the present invention, is soconstructed as to deliver fuel to the secondary air passage 94immediately anterior to the valve 96 and, therefore, is less eifectivebefore said valve 96 starts to open than after its opening movementbegins. This form of pump is provided according to this invention forthe reason that prior to the opening of the valve 96 it has been foundthat the suction at the fuel nozzles increases more rapidly on openingof the throttle than it does after the valve 96 is partly open and is,therefore, effective to supply a mixture of more nearly the desiredproportions under these conditions, while the velocity through theprimary tubes under such conditions is sufiicient to supply the enrichedmixture to the engine cylinders rapidly enough to effect relativelysmooth and rapid acceleration of the engine. In most earlier devices ofthis character, the pump has been designed. to supply fuel to theprimary mixture passages and is substantially as effective on openingmovements of the primary throttle prior to the opening of the valve 96as it is subsequent to the opening of such valve. It has been foundunnecessary to supply as much additional fuel during a given timeinterval following an opening movement of the throttle prior to theopening of the valve 96, but because the acceleration is slower thanwhen the opening of the throttle occurs after the opening of valve 96.Because of the slower speed, the period of acceleration is longer,however, and it is desirable to supply the additionalfuelforalongertime.This is accomplished by the arrangement of pump above referred to whichdelivers to the secondary air passage. According to this invention apump has been provided which comprises a cylinder 110 formed in thecasting 30 and a piston 112 slidable therein. The latter is pivotallysecured to an operating rod 116 which extends upwardly through the topof the fuel reservoir and at its upper end is pivotally connected by apin and slot connection to an operating arm 118 pivotally mounted on apin 120 screwed into the main housing. A roller 122 is pivotally mountedon the other end of the arm 118 and is engaged by a earn 124 fixed on aspindle 126 projecting from the end of the primary throttle. The pumppiston is moved downwardly by the cam on every opening movement of theprimary throttle to force fuel through a fuel delivery passage 128connected with the cylinder 110 near its bottom and having anenlargement 130 at its upper end at which a check valve 132 is receivedto prevent return of the fuel to the pump cylinder on closing movementof the air valve. The passage 128 communicates above the check valvewith a horizontal passage 134 leading to a well 136, formed in thecasting 30 and communicating with the atmosphere through an orifice 138,so that atmospheric pressure is maintained within the well. A deliverytube 140 is received in a bore in the main housing and extends into thewell 136, terminating adjacent the bottom thereof, while the upper endof this delivery tube is provided with a restriction 142 to limit therate of flow of fuel from said well and to effect atomization of thefuel delivered. On every operation of the pump piston, surplus fuelabove the capacity of the well is discharged through the orifice 138into the main fuel reservoir, the suction of the manifold iscommunicated to the upper end of the delivery tube 140 and the fuelretained in the well is drawn out of such well into the secondary airpassage 94 until the level of fuel in the well falls below the lower endof the tube.

It will be clear that a greater amount of fuel is drawn into the airpassage 94 when the throttle is opened relatively slowly and that suchfuel is supplied to said air passage through a greater period of timethan when the throttle is opened relatively rapidly. On relatively slowopening movements of the throttle, the fuel is supplied to the wellrelatively slowly and such fuel is mostly drawn into the air passage 94with but little overflowing from the well and returning to the main fuelreservoir through the orifice 138. Also when the throttle is openedrelatively slow- 1y fuel will be supplied to the well by the pump anddrawn therefrom through the tube 140 for a greater length of time thanwhen the throttle is opened rapidly, for when this occurs, the fuel issupplied to the well by the pump very rapidly and a larger proportion ofit is returned to the main fuel reservoir through the orifice 138; whilethe relatively small amount of fuel that does not so overflow is drawninto the air passage 94 much more rapidly than when the throttle isopened slowly.

The secondary mixing chambers may be of any desired construction whichwill accelerate the flow of air past the ends of the primary mixtureconduits and as illustrated, each secondary mixing chamber comprises aVenturi tube 122, positioned adjacent the outlet end of the primarymixture conduit. Each Venturi is provided with an exterior rib 144,adapted to be clamped between shoulders on the manifold and engineblocks respectively, when the device is assembled.

The Venturi tubes serve to accelerate the flow through the primarymixture conduits in the manner fully disclosed in the earlierapplication. The advantageous results produced by the fuel pumpdisclosed above, will be obvious from the description of the operationof said pump and need not be repeated.

In the event of an excess accumulation of fuel in the secondary airpassage before the valve 96 opened, as might occur in the event that thethrottle were opened and closed several times to a moderate extent butnot enough to cause opening of the valve 96, some of the accumulatedfuel might pass through the holes 71 into the primary mixing chambers.

While the form of embodiment of the present invention as hereindisclosed, constitutes a preferred form, it is to be understood thatother forms might be adopted, all coming within the scope of the claimswhich follow.

What is claimed is as follows:

1. A charge forming device for internal combustion engines comprising, amixture passage having a mixing chamber therein, means for supplyingfuel and air to the mixture passage, a secondary air passage adapted tosupply additional air to said mixing chamber at a point remote from themixing chamber under certain operating conditions, a throttle, and meansoperated by the throttle on opening movements thereof under anyoperating conditions for supplying fuel to the secondary air passage.

2. A charge forming device for internal combustion engines comprising, amixture passage having a mixing chamber therein, means for supplyingfuel and air to the mixing chamber, a secondary air passage adapted tosupply additional air to said mixture passage at a point remote from themixing chamber, a throttle, and a fuel pump operated by the throttle onopening movements thereof for supplying fuel to the secondary airpassage.

3. A charge forming device for internal combustion engines comprising, amixture passage, means for supplying fuel and air to the mixturepassage, a secondary air passage adapted to supply additional air tosaid mixture passage, a

throttle, a valve in the secondary air passage operated by said throttlefor controlling the flow therethrough and means also operated by thethrottle on opening movements thereof for supplying fuel to saidsecondary air passage.

4. A charge forming device for internal combustion engines comprising, amixture passage, means for supplying fuel and air to the mixturepassage, a secondary air passage adapted to supply additional air tosaid mixture passage, a throttle, a valve in the secondary air passageoperated by said throttle for controlling the flow therethrough andmeans also operated by the throttle on opening movements thereof forsupplying fuel to said secondary air passage adjacent the valve therein.

5. A charge forming device for internal combustion engines comprising, amixture passage, means for supplying fuel and air to the mixturepassage, a secondary air passage adapted to supply additional air tosaid mixture passage, a throttle, a valve in the secondary air passageoperated by said throttle for controlling the flow therethrough andmeans also operated by the throttle on opening movements thereof forsupplying fuel to said secondary air passage anterior to the valvetherein.

6. A charge forming device for internal combustion engines comprising, amixture passage having a mixing chamber therein, means for supplyingfuel and air to the mixing chamber, a secondary air passage adapted tosupply additional air to said mixture passage, a throttle, a valve insaid secondary air passage adapted to be opened after the throttle hasmade a predetermined opening movement, and means operated by thethrottle on opening movements thereof for supplying fuel to saidsecondary air passage at a point remote from the mixing chamber bothbefore and after the opening of said valve.

7. A charge forming device for internal combustion engines comprising, amixture passage, means for supplying fuel and air to the mixturepassage, a secondary air passage adapted to supply additional air tosaid mixture passage, a throttle, a valve in said secondary air passage,means operated by the throttle for opening said valve after the throttlehas made a predetermined opening movement, and means operated by thethrottle on opening movements thereof for supplying fuel to saidsecondary air passage both before and after opening of said valve.

8. A charge forming device for internal combustion engines comprising, amixture passage, means for supplying fuel and air to the mixturepassage, a secondary air passage adapted to supply additional air tosaid mixture passage, a throttle. a valve in said secondary air passageadapted to be opened after a predetermined opening movement of thethrottle, means operated by the throttle on opening movements thereoffor supplying fuel to said secondary air passage both before and afterthe opening of said valve, and a passage connecting the secondary airpassage with the mixture passage, whereby some of the fuel supplied tothe secondary air passage may iiow into the primary mixture passagebefore the opening of said valve.

9. A charge forming device for internal combustion engines comprising amixture passage having a mixing chamber formed therein, means forsupplying fuel and air to said mixing chamber, a throttle, a secondaryair passage adapted to admit additional air to the mixture passage at apoint remote from the mixing chamber, and means operated by the throttlefor supplying fuel to said secondary air passage at a point relativelyclose to the intake end of the secondary air passage, during theacceleration period.

10. A charge forming device for internal combustion engines comprising amixture passage having a mixing chamber formed therein, means forsupplying fuel and air to said mixing chamb r, a throttle, a secondaryair passage adapted to admit additional air to the mixture passage at apoint remote from the mixing chamber, a valve in said secondary airpassage, and means operated by the throttle for supplying fuel to saidsecondary air passage at a point anterior to said valve.

11. A charge forming device for internal combustion engines comprising amixture passage having a mixing chamber formed therein, means forsupplying fuel and air to said mixing chamber, a throttle, a secondaryair passage adapted to admit additional air to the mixture passage, avalve in said secondary air passage adapted to be opened during certainopening movements of the throttle only, and means operated by thethrottle on all opening movements thereof for supplying fuel to saidsecondary air passage anterior to said valve, whereby on openingmovements of the throttle when the valve remains closed, fuel isaccumulated in the secondary air passage to enrich the mixture wheneversaid valve begins to open.

12. A charge forming device for internal combustion engines comprising amixture passage having a mixing chamber formed therein, means forsupplying fuel and air to said mixing chamber, a throttle, a secondaryair passage adapted to admit additional air to the mixture passage, aval in said secondary air passage adapted to be or led only after thethrottle has made a predetermined movement, a fuel pump operated by thethrottle, and a fuel delivery conduit extending from said pump to thesecondary air passage at a point anterior to said valve, whereby whenthe valve is closed fuel is supplied to said air passage by the actionof the pump alone, but when the valve is open said fuel delivery conduitis subject to the action of engine suction.

13. A charge forming device for internal combustion engines comprising amixture passage having a mixing chamber formed therein, means forsupplying fuel and air to said mixing chamher, a throttle, a secondaryair passage adapted to admit additional air to the mixture passage, avalve in said secondary air passage adapted to be opened only after thethrottle has made a predetermined movement, a fuel pump operated by thethrottle, a reservoir supplied with fuel by said pump, a delivery tubeextending from the reservoir into said secondary air passage at a pointanterior to the valve, whereby engine suction communicated to saiddelivery tube is increased when the valve is opened.

l l. A charge forming device for internal combustion engines comprisinga secondary mixing chamber, a primary mixture passage adapted to delivera primary mixture of fuel and air to said secondary mixing chamber,means for supplying fuel and air to said primary mixture passage, aprimary throttle in said passage controlling the flow therethrough, asecondary air passage adapted to supply air to the secondary mixingchamber and means operated by the primary throttle for supplying fuel tothe secondary air passage during the acceleration period.

15. A charge forming device for internal combustion engines comprising asecondary mixing chamber, a primary mixture passage adapted to deliver aprimary mixture of fuel and air to said secondary mixing chamber, meansfor supplying fuel and air to said primary mixture passage, a primarythrottle in said passage controlling the how therethrough, a secondaryair passage adapted to supply air to the secondary mixing chamber andmeans operated by the primary throttle on all opening movements thereoffor supplying fuel to the secondary air passage during the accelerationperiod.

16. A charge forming device for internal combustion engines comprising asecondary mixing chamber, a primary mixture passage adapted to deliver aprimary mixture of fuel and air to said secondary mixing chamber, meansfor supplying fuel and air to said primary mixture passage, a primarythrottle in said passage controlling the flow therethrough, a secondaryair passage adapted to supply air to the secondary mixing chamber, avalve in said secondary air passage and means operated by the primarythrottle for supplying fuel to said secondary air passage at a pointanterior to the valve therein.

17. A charge forming device for internal combustion engines comprising asecondary mixing chamber, a primary mixture passage adapted to deliver aprimary mixture of fuel and air to said secondary mixing chamber, meansfor supplying fuel and air to said primary mixture passage, a primarythrottle in said passage controlling the flow therethrough, a secondaryair passage adapted to supply air to the secondary mixing chamber, avalve in said secondary air passage adapted to be opened during a partof the opening movement of the primary throttle and means operated bythe primary throttle for supplying fuel to the secondary air passageduring the entire opening movement thereof.

18. A charge forming device for internal combustion engines comprising asecondary mixing chamber, a primary mixture passage adapted to deliver aprimary mixture of fuel and air to said secondary mixing chamber, meansfor supplying fuel and air to said primary mixture passage, a primarythrottle in said passage controlling the flow therethrough, a secondaryair passage adapted to supply air to the secondary mixing chamber, avalve in said secondary air passage adapted to be opened during a partof the opening movement of the primary throttle and means operated bythe primary throttle during its entire opening movement for supplyingfuel to the secondary air passage anterior to the valve therein, wherebyfuel is accumulated in said air passage prior to the opening of saidvalve.

19. A charge forming device for internal combustion engines comprising asecondary mixing chamber, a primary mixture passage adapted to deliver aprimary mixture of fuel and air to said secondary mixing chamber, meansfor supplying fuel and air to said primary mixture passage, a primarythrottle in said passage controlling the flow therethrough, a secondaryair passage adapted to supply air to the secondary mixing chamber, meanssubject to the engine suction and normally ineffective for supplyingfuel to the secondary air passage during the acceleration period andmeans operated by the primary throttle for rendering said last namedmeans eifective.

20. A charge forming device for internal combustion engines comprising asecondary mixing chamber, a primary mixture passage adapted to deliver aprimary mixture of fuel and air to said secondary mixing chamber, meansfor supplying fuel and air to said primary mixture passage, a primarythrottle in said passage controlling the flow therethrough, a secondaryair 100 passage adapted to supply air to the secondary mixing chamberand means controlled jointly by the engine suction and the primarythrottle for supplying fuel to the secondary air passage during theacceleration period.

21. A charge forming device for internal combustion engines comprising aplurality of primary mixture passages adapted to supply a primarymixture of fuel and air to a plurality of secondary mixing chambers,means for supplying 110 fuel and air to said primary mixture passages,

a primary throttle for controlling the flow of mixture through saidprimary mixture passages,

a single secondary air passage for supplying air to all of saidsecondary mixing chambers and 115 means operated by the primary throttlefor supplying fuel to said secondary air passage during the accelerationperiod.

FRED E. ASELTINE.

